Several techniques have been explored to simplify microvascular repairs. One of these techniques, laser assisted microvascular anastomoses (LAMA) has been studied extensively, with limited clinical use. Major impediments to the acceptance of LAMA by microsurgeons were concerns with low acute tensile strength, and the subjective visual endpoint for tissue fusion. These problems have been addressed recently via the use of biological solders to increase tensile strengths, and the use of real time temperature control systems for reproducible LAMA. Whereas these improvements have increased the overall safely of the LAMA procedure, failures second-ary to the thromboses of small microvessels ( less than 0.5 mm), which are also a major problem in sutured repairs, will remain pervasive. The objective of this proposal is to integrate temperature controlled laser welding techniques with novel types of tissue solders to provide in situ delivery of antithrombotic agents at the microvascular repair site. By adding anti-coagulants or thrombolytic drugs to the tissue solders, and then thermally denaturing the bulk solders during LAMA, non-immunogenic, bioactive structure results. As the solders are denatured by the healing process, the drug should be delivered to the repair site, providing therapeutic in situ dosages. In the Phase I studies, this novel tissue repair technology will be used in a microvascular thrombosis model to measure the patency rate, as compared to sutured repairs. This new repair technology should ultimately result in significantly increased postoperative success rates for microvascular repairs. PROPOSED COMMERCIAL APPLICATION This research involves several novel technologies, whose combination may lead to a significant improvement in the clinical outcome of microvascular repairs. The use of the resulting methodology for in situ drug delivery may also be applicable to increase the postoperative success rate for the repair of larger vessels, which accounts for over 500,000 procedures per year in the U.S.